The safest method is to download the file directly from Dell Support.
Many Latitude 3420 models store administrator passwords directly in the BIOS chip. Clearing the CMOS battery often won't work on modern Dell laptops. Flashing a clean, password-free BIOS bin file is the only way to remove a forgotten supervisor or HDD password.
Create a Bootable USB Drive:
Update BIOS:
If the boot block is intact:
However, this fails if the ME region is corrupt. That requires a pre-modified bin.
